Nodulosporic acid and two related components are antiparasitic agents and ectoparasiticidal agents isolated from the fermentation culture of Nodulisporium sp. MF-5954 (ATCC 74245). These three compounds have the following structures: nodulisporic acid (compound A) ##STR1##
29,30-dihydro-20,30-oxa-nodulisporic acid (compound B) ##STR2##
31-hydroxy-20,30-oxa-29,30,31,32-tetrahydro-nodulisporic acid (compound C) ##STR3##